Electromagnetic actuated exhaust gas recirculation valve

Abstract

An automotive emission control valve including a body having an internal main flow passage between a first port and a second port, a valve seat circumscribing a transverse cross-sectional area of the passage, a valve member including a non-flow-through valve head, an electromagnetic actuator providing a magnetic circuit path that includes an armature for operating the valve member to selectively seat and unseat the valve head on and from the valve seat. The armature comprising a unitary ferromagnetic member having an axial end which contains a walled hole that extends interiorly of the ferromagnetic member and ends at a surface of a transverse wall of the ferromagnetic member. The valve member including a valve stem having a free distal end. The valve further including a locator which is joined to the free distal end of the valve stem. The locator bearing against the surface of the transverse wall.

We claim: 
     
       1. An automotive emission control valve comprising a body having an internal main flow passage between a first port and a second port, a valve seat circumscribing a transverse cross-sectional area of the passage, a valve member including a valve head, an electromagnetic actuator providing a magnetic circuit path that includes an armature for operating the valve member to selectively seat and unseat the valve head on and from the valve seat, the armature having a unitary ferromagnetic member with respective opposite ends, each of which contains a respective walled hole that extends interiorly of the ferromagnetic member and a transverse wall disposed between the walled holes, the transverse wall having oppositely facing surfaces, a sensor including a sensor shaft extending into one of the walled holes to bear against one of the oppositely facing surfaces of the transverse wall, and the valve member including a stem extending into the other of the walled holes to bear against the other of the oppositely facing surfaces of the transverse wall. 
     
     
       2. An automotive emission control valve as set forth in claim 1 further including at least one fluid passageway that extends through the transverse wall and is open to both of the walled holes for conveying fluid between the walled holes. 
     
     
       3. An automotive emission control valve as set forth in claim 2 in which the valve stem has a free distal end, and including a locator which is joined to the free distal end of the valve stem, the locator bearing against the other of the oppositely facing surfaces of the transverse wall. 
     
     
       4. An automotive emission control valve as set forth in claim 3 in which the magnetic path includes stator structure including a multi-part pole piece through which the valve stem passes, the pole piece comprising a central hub part through which the stem passes and a rim part that extends circumferentially about the central hub part and that is joined to the central hub part. 
     
     
       5. An automotive emission control valve as set forth in claim 4 further including a bearing member disposed in the body and comprising a through-hole, the valve stem extending from the valve head to substantially occlude the through-hole with a close sliding fit therein, the bearing member having an end which is spaced from the pole piece, the valve stem extending from the bearing member, and further including a deflector circumferentially bounding the stem between the bearing member and the pole piece, the body including an air circulation space adjacent the actuator proximate the pole piece and circumferentially bounding the deflector. 
     
     
       6. An automotive emission control valve as set forth in claim 5 in which the body comprises a wall circumferentially bounding the air circulation space outwardly of the deflector and comprising air circulation holes, the air circulation holes including integral liquid drains forming the lowermost points of the air circulation holes. 
     
     
       7. An automotive emission control valve as set forth in claim 1 further including a sensor spring for biasing the sensor shaft to bear against the one of the oppositely facing surfaces of the transverse wall and a valve spring for biasing the valve member to bear against the other of the oppositely facing surfaces of the transverse wall. 
     
     
       8. An automotive emission control valve as set forth in claim 7 further including a fluid passageway that extends through the transverse wall and is open to both of the walled holes for conveying fluid between the walled holes. 
     
     
       9. An automotive emission control valve as set forth in claim 1 in which the valve stem has a free distal end, and including a locator which is joined to the free distal end of the valve stem and bears against the other of the oppositely facing surfaces of the transverse wall. 
     
     
       10. An automotive emission control valve as set forth in claim 1 in which the magnetic circuit path comprises stator structure including a pole piece through which the valve stem passes, and further including a bearing member disposed in the body and comprising a through-hole, the valve stem extending from the valve head to substantially occlude the through-hole with a close sliding fit therein, the bearing member having an end which is spaced from the pole piece, the valve stem extending from the bearing member to pass through the pole piece, and further including a deflector circumferentially bounding the valve stem between the bearing member and the pole piece, the body including an air circulation space adjacent the actuator proximate the pole piece and circumferentially bounding the deflector. 
     
     
       11. An automotive emission control valve as set forth in claim 10 in which the body comprises a wall circumferentially bounding the air circulation space outwardly of the deflector. 
     
     
       12. An automotive emission control valve as set forth in claim 10 in which bearing member through-hole has a circular transverse cross section providing for the close sliding fit of the valve member therein. 
     
     
       13. An automotive emission control valve as set forth in claim 1 in which the valve comprises an engine exhaust gas recirculation valve wherein the body comprises a base containing the main flow passage and the first and second ports, one of the ports receiving engine exhaust gas to be recirculated, and the other of the ports conveying engine exhaust gas that has passed through the main flow passage to dope induction flow into an engine. 
     
     
       14. An automotive emission control valve as set forth in claim 13 in which the actuator comprises a shell that is associated with the base to form the body, and a portion of the shell also forms a portion of the magnetic circuit path. 
     
     
       15. An automotive emission control valve as set forth in claim 14 in which the actuator comprises a pole piece forming another portion of the magnetic circuit path, the valve stem passes through the pole piece, and the shell bounds an air circulation space that is disposed between the pole piece and the base and that circumferentially bounds a portion of the valve stem, the shell containing air circulation holes at the air circulation space. 
     
     
       16. An automotive emission control valve as set forth in claim 15 in which the pole piece comprises a central hub part through which the stem passes and a rim part that extends circumferentially about the central hub part and that is joined to the central hub part and is in engagement with the shell. 
     
     
       17. An automotive emission control valve comprising a body having an internal main flow passage between a first port and a second port, a valve seat circumscribing a transverse cross-sectional area of the passage, a valve member including a valve head, an electromagnetic actuator comprising a magnetic circuit path that includes an armature for operating the valve member to selectively seat and unseat the valve head on and from the valve seat, the armature comprising a unitary ferromagnetic member having an axial end which contains a walled hole that extends interiorly of the ferromagnetic member and ends at a first surface of a transverse wall of the ferromagnetic member, the valve member including a valve stem having a free distal end, and further including a locator which is joined to the free distal end of the valve stem, the locator bearing against the surface of the transverse wall. 
     
     
       18. An automotive emission control valve as set forth in claim 17 further including at least one fluid passageway that extends through the transverse wall and is open to the walled hole for conveying fluid into and out of the walled hole. 
     
     
       19. An automotive emission control valve as set forth in claim 17 further including a sensor having a sensor shaft, the transverse wall having a second surface opposite the first surface, and the sensor shaft bearing against the second surface of the transverse wall. 
     
     
       20. An automotive emission control valve as set forth in claim 19 in which the ferromagnetic member comprises a second axial end that is opposite the first axial end and that contains a second walled hole that extends interiorly of the ferromagnetic member and ends at the second surface of the transverse wall, the sensor shaft extending into the second walled hole to bear against the second surface of the transverse wall. 
     
     
       21. An automotive emission control valve as set forth in claim 20 further including a sensor spring for biasing the sensor shaft to bear against the second surface of the transverse wall and a valve spring for biasing the valve member to cause the locator to bear against the first surface of the transverse wall. 
     
     
       22. An automotive emission control valve as set forth in claim 21 further including a fluid passageway that extends through the transverse wall and is open to both of the walled holes for conveying fluid between the walled holes. 
     
     
       23. An automotive emission control valve comprising a body having an internal main flow passage between a first port and a second port, a valve member associated with the main flow passage, an electromagnetic actuator comprising a magnetic circuit path that includes an armature for operating the valve member to control flow through the passage, the armature comprising a walled hole extending into the armature and ending at a transverse wall of the armature, the valve member including a valve stem having a free distal end, and further including a locator which is joined to the free distal end of the valve stem, the locator bearing against the transverse wall. 
     
     
       24. An automotive emission control valve as set forth in claim 23 further including at least one fluid passageway that extends through the transverse wall and is open to the walled hole for conveying fluid into and out of the walled hole. 
     
     
       25. An automotive emission control valve as set forth in claim 23 further including a sensor having a sensor shaft bearing against the transverse wall. 
     
     
       26. An automotive emission control valve as set forth in claim 25 in which the armature comprises opposite axial ends, the walled hole extending into the armature from one axial end, and including a second walled hole extending into the armature from the opposite axial end to the transverse wall, the sensor shaft extending into the second walled hole to bear against the transverse wall. 
     
     
       27. An automotive emission control valve as set forth in claim 26 further including a sensor spring for biasing the sensor shaft to bear against the transverse wall and a valve spring for biasing the valve member to cause the locator to bear against the transverse wall. 
     
     
       28. An automotive emission control valve as set forth in claim 27 further including a fluid passageway that extends through the transverse wall and is open to both of the walled holes. 
     
     
       29. An automotive emission control valve as set forth in claim 23 in which the armature comprises a unitary ferromagnetic member that contains the walled hole and transverse wall, the hole ends at a surface of the transverse wall, and the locator bears against the surface of the transverse wall. 
     
     
       30. An electric exhaust gas recirculation (EEGR) valve for an internal combustion engine comprising body structure, an entrance at which engine exhaust gas to be recirculated enters the body structure, a passage that extends through the body structure for conveying engine exhaust gas that has entered the entrance, an exit at which engine exhaust gas that has passed through the passage exits the body structure, a valve mechanism disposed within the body structure for controlling flow through the passage, an electromagnetic actuator disposed within the body structure and comprising an armature for operating the valve mechanism, the actuator further comprising stator structure providing a magnetic circuit path that includes the armature, the valve shaft structure comprising a valve shaft having a free distal end and a locator that bears against the armature the locator being axially positionable on the valve shaft. 
     
     
       31. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 30 wherein the locator comprises a sidewall fitting to the valve shaft and a domed end wall that bears against the armature. 
     
     
       32. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 30 wherein the locator sidewall is disposed around a serrated zone on an outer surface of the valve shaft. 
     
     
       33. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 30 wherein the armature comprises a hole extending into the armature, the hole ends at a transverse wall of the armature, and the locator bears against the transverse wall. 
     
     
       34. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 33 wherein the locator comprises a domed end wall that bears against the transverse wall. 
     
     
       35. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 30 in which the stator structure includes a pole piece and the locator is positioned on the valve shaft to set a dimensional relationship between the armature and the pole piece. 
     
     
       36. An electric exhaust gas recirculation (EEGR) valve as set forth in claim 30 in which the valve mechanism includes a spring related to the locator such that the spring is compressed in an amount corresponding to the position of the locator on the valve shaft. 
     
     
       37. A method of calibrating an electric exhaust gas recirculation valve for an internal combustion engine comprising the steps of: providing an electric exhaust recirculator valve having a body structure, an entrance at which engine exhaust gas to be recirculated enters the body structure, a passage that extends through the body structure for conveying engine exhaust gas that has entered the entrance, an exit at which engine exhaust gas that has passed through the passage exits the body structure, a valve mechanism disposed within the body structure for controlling flow through the passage, an electromagnetic actuator disposed within the body structure and comprising an armature for operating the valve mechanism, the actuator further comprising stator structure providing a magnetic circuit path that includes the armature, the valve shaft structure comprising a valve shaft having a free distal end and a locator that bears against the armature;   positioning the locator axially on the valve shaft; and   joining the locator and the valve shaft.   
     
     
       38. A method as set forth in claim 37 in which the joining step comprises crimping the locator onto the valve shaft. 
     
     
       39. A method as set forth in claim 37 in which the stator structure comprises a pole piece, and the step of positioning the locator axially on the valve shaft comprises setting a dimensional relationship between the armature and pole piece. 
     
     
       40. A method as set forth in claim 37 in which the valve mechanism comprises a spring, and the step of positioning the locator axially on the valve shaft comprises setting compression of the spring.